I just had a strange occurrence with a cup of water. I'll explain this the best that I can... I failed science, so I have no idea how this happened.

I left a cup of water unattended for about 2 hours. It is an 18-ounce cup, about 5 inches tall. The cup was about 1 inch full of tap water at the time of the incident.
There was a plastic straw resting in the cup, about 7.5 inches in length, and 1/4 of an inch in diameter. The straw is an accordion-style flexible straw, with the flexible part about 6 inches up the straw. The straw was straight and not stretched out at the time of the incident.
The elevation was about 5,850 feet above sea level. It was in a basement room. I estimate that the room temperature was about 70 degrees Fahrenheit.

Now for the incident. When I walked into the room to get the cup, I noticed that the straw was almost completely full of water. Despite only an inch of water in the cup, the straw was full of water up to the flexible part (6 inches.) Nothing was obstructing any part of the straw. I slowly pulled the straw up, and the water slowly drained out as I pulled.

So... How the hell did the water rise almost to the top of the straw? I have never seen this, and I can't replicate it. And I don't even know how to start Googling this.

So... Is this a real thing that happens, or am I hallucinating? (Full disclosure - I have been having some minor psychotic episodes recently since starting a new medication.)
Anyone?

Here is a drawing of what it looked like. It isn't pretty... I failed art class, too.
-edit- The actual cup is thin plastic and mostly opaque. The color of the cup is red.

Changes in pressure in the straw are the most likely explanation. Somehow the air pressure in the straw was reduced over time, probably as a result of cooling over time. As air temperature reduces, so does air pressure.

This is more from an engineering background than actual fundamental physics, so I may be wrong.

I believe your problem deals with pressure. Air and gravity are pressing the water down which can force water up a straw as an escape. gravity also applies a down force to the water in the straw but it is possible for the force of air(and gravity if the straw is perfectly placed.) you just happend to find the sweet spot in water height, straw placement, and a few other facters to make this work.) You also left it alone or it would have stopped the process. Warning I am a biology major not a physics major so I may have been incorrect about some of this. Still I hope this helped.

Thirsty ghosts. Have you had any family member or ancestor die in a desert ?

capillary action most likely ninja'd ... with link too :)

I think that is one of those new kind of straws where you don't have to suck with your mouth at all, but the liquid just rushes through the straw right into your mouth, as soon as you dip the other end in the liquid.

I think I saw a patent application for that somewhere.

Shit! Don Herbert is dead, just when you need him!

My Canadian bretherin will get that reference. :D

Capillary action. Similar to how a tissue soaks up water several centimeters away from the water-surface.

Yep. capillary action is probably the correct answer. Can be assisted by a temperature difference. Was perhaps the top of the straw warmer than the bottom? (sun shining on it or something) That could increase the normal capillary effect, so that it gets even more noticeable.

Capillary action alone won't draw water 5 inches up a 0.25" diameter drinking straw. That's huge. It should be less than a tenth that climb.

Combined action of :
capillarity
atmospheric pressure
vaporisation (in the straw)

Your water was playing[url=https://secure.gog.com/gamecard/puddle ] this [/url] when you weren't looking.

I can't believe no one said "Magic!" ;-p

You don't actually say (and perhaps dont actually know) if there was water in the straw when you left the room.

if you had been drinking through the straw before you left then the question we should be asking might be "why did the water not drain from straw?"

And the answer might simply be - an air bubble.